The National Airspace System (NAS) Plan for Facilities, Equipment and Associated Development has set a framework for the modernization of the NAS for the next decade. It was developed with specific overall goals in a mind. These include the replacement and modernization of an aging air traffic control and navigation system, the development of a total system related to the specific needs of the user community, and the design of that system to serve as a basis for further enhancement of safety, improved efficiency, and reduced operation costs. The primary objective of this document is to provide a comprehensive and accurate representation of the requirements of the entire aviation community, while accommodating modifications or new requirements in response to changing operational needs during the NAS evolution. It is not a stand alone document, but one that is support by a myriad of other documents and specifications.